Joint geophysical and hydrological inversion of a mesoscale laboratory experimental dataset

A core goal of hydrogeophysics is mapping of geophysical data into temporal and spatial hydrological information. A fundamental question in this effort is the uncertainty associated with this mapping, and the effect and benefits of integrating point measurements of hydrological information such as moisture content in the geophysical inversion. An infiltration experiment was performed at INEEL to address this question. The goal of this experiment was to construct the general patterns of the wetting front and spatial distribution of the moisture content from the inverted resistivity field. 3D timelapse ERT data and 20 point measurements of moisture change over the experiment as well as the infiltration time history were collected automatically. The point samples of moisture content data were translated into electrical resistivities as prior information for the ERT inversion. This inversed resistivity field was translated into moisture content map used as prior information for hydrological inversion. The 3-D hydrologic inversion model was able to derive 3-D distribution of unsaturated hydraulic conductivity and moisture release curves for water movements. The output of the inverted moisture content map was translated into an electrical resistivity map as prior information for the ERT inversion, and these steps were repeated iteratively until no further improvement on the inversed resistivity field, moisture content distribution and saturated hydraulic conductivity field were obtained. Set up of analysis of this data through a web based interface in which data and models are accessible through a relational database allows for both research reproducibility and "what if" scenarios in which the effect on the end result of removing specific data can be easily investigated and evaluated.